How Does Green Coffee Bean Extract Work… What is The Mechanism?

However, the main active ingredient is believed to be the chlorogenic acid.

Some human studies suggest that it can reduce the absorption of carbohydrates from the digestive tract, which lowers blood sugar and insulin spikes (5, 6).

If this is true, then taking green coffee bean extract would be like eating a slightly lower carbohydrate diet.

Other studies (in mice and rats) have shown that chlorogenic acid can reduce body weight, reduce fat absorbed from the diet, reduce fat stored in the liver and improve the function of the fat burning hormone adiponectin (7, 8).

Chlorogenic acid has also been shown to drastically improve cholesterol and triglyceride levels in rats. These are important risk factors for heart disease (9).

Bottom Line: Green coffee has been shown to inhibit weight gain in animal studies. This may be due to decreased absorption of carbohydrates from the diet, or via some other mechanism.

What do The Human Studies Say?

One of them included 30 overweight individuals and went on for 12 weeks.

There were two groups… one consumed regular Instant coffee, while the other consumed Instant coffee enriched with 200 mg of Green Coffee Bean Extract (10).

Neither group was instructed to change their diet or exercise habits.

This graph shows the weight changes in the two groups, from 0-12 weeks:

As you can see, the group taking the instant coffee with green coffee bean extract lost 11.9 pounds (5.4 kg), while the group taking plain instant coffee lost only 3.7 pounds (1.7 kg).

Body fat percentage also went down by 3.6% in the green coffee extract group, compared to 0.7% in the other group.

More studies

Several other studies have reported significant weight loss in people taking green coffee bean extract (11).

However, it’s important to keep in mind that some of these studies were sponsored by companies that profit from sales of green coffee beans.

This doesn’t necessarily mean that the results are invalid, but it is known that the funding source of a study can have a significant effect on the outcome. For this reason, it is a good idea to be extra skeptical of industry funded research (12).

“… the results from these trials are promising, but the studies are all of poor methodological quality. More rigorous trials are needed to assess the usefulness of GCE as a weight loss tool.”

I agree. The little evidence we do have is pretty promising, but larger and longer-term trials are needed before any firm recommendations can be made.

Bottom Line: Several controlled trials in humans show that green coffee bean extract can lead to significant weight loss. However, these studies were relatively small and some of them were industry sponsored.

Does Green Coffee Extract Have Other Health Benefits?

Green coffee may positively affect how our bodies absorb and use carbohydrates.